Microencapsulation of cells within microfluidic devices enables explicit control of the membrane thickness or cell density, resulting in improved viability of the transplanted cells within an aggressive immune system. In this study, living cells (3T3 and L929 fibroblast cells) are encapsulated within a semi-permeable membrane (calcium crosslinked alginate gel) in two different device designs, a flow focusing and a core-annular flow focusing geometry. These two device designs produce a bead and a long microfibre, respectively. For the alginate bead, an alginate aqueous solution incorporating cells flows through a flow focusing channel and an alginate droplet is formed from the balance of interfacial forces and viscous drag forces resulting from the continuous (oil) phase flowing past the alginate solution. It immediately reacts with an adjacent CaCl2 drop that is extruded into the main flow channel by another flow focusing channel downstream of the site of alginate drop creation. Depending on the flow conditions, monodisperse microbeads of sizes ranging from 50-200 μm can be produced. In the case of the microfibre, the alginate solution with cells is extruded into a continuous phase of CaCl2 solution. The diameter of alginate fibres produced via this technique can be tightly controlled by changing both flow rates. Cell viability in both forms of alginate encapsulant was confirmed by a LIVE/DEAD cell assay for periods of up to 24 hours post encapsulation.
|Number of pages||8|
|Journal||Korea Australia Rheology Journal|
|Publication status||Published - 2007 Nov|
- Calcium alginate gel
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics